This came up at lunch today when a friend of mine brought up that he had recently watched the Nova episode of Fabric of the Cosmos where they talk about spacetime as a sort of loaf where relative motion has the effect of cutting different angled slices out of the "loaf" of space time (for those who haven't seen the episode, it's basically textbook stuff on the relativity of simultaneity). Anyway, that got me thinking about it. It's entirely possible for a distant observer moving towards me at great speed to observe that his "now-slice" contains things that from my perspective haven't happened yet, but these things will happen, does this imply some kind of determinism? I realize that there's no way for that distant observer to relay that information to me before it happens thanks to the limit of information being the speed of light I will always observe him observing my past, never my future. It seems like I'm not the only person to have ever thought about this, I stumbled upon this when I searched for "Relativistic Determinism". The more I think about it, maybe it's not that big of a deal (other than it being really weird), but is the logic sound? Is it possible for a distant observer to observe something that from my perspective hasn't happened yet? Or, in other words, is it valid to think of "all of time" existing in the same way we think "all of space" exists?